Polycondensation resins such as polyesters and polyamide have been used in various applications, such as films, sheets, and fibers, utilizing their chemical and physical properties, and various studies have been made on catalysts for accelerating a polycondensation reaction and promoters for enhancing the activity of the catalyst depending upon the applications of the resins obtained.
For example, as a catalyst used in the production of a polycondensation resin used in a resin binder for a toner, various tin compounds have been studied, taking into consideration not only catalytic activity but also influences to the properties of the toner such as triboelectric chargeability. In recent years, a tin(II) compound without containing a Sn—C bond is more likely to be used as a catalyst than a tin compound having a Sn—C bond, such as dibutyltin oxide, from the viewpoint of safety or the like (see JP-A-2003-186250, or the like).
On the other hand, reports have been made that a polycondensation reaction is accelerated by using a tin(II) compound without containing a Sn—C bond together with an amide compound or an amine compound, thereby shortening the reaction time, whereby a resin having a shorter heat history is obtained (see JP-A-2006-350035, and the like).
In addition, as a catalyst to be used as a substitute for a tin compound having a Sn—C bond such as dibutyltin oxide, a titanium compound is likely to be preferably used, from the viewpoint of safety, or the like (see JP-A-2003-201342 (corresponding to US-A-2003-158372), JP-A-2004-151246 (corresponding to US-A-2004-086797), JP-A-2006-91318, and the like).